hdu 1317 XYZZY

http://acm.hdu.edu.cn/showproblem.php?pid=1317

 1 #include <cstdio>

 2 #include <queue>

 3 #include <cstring>

 4 #include <algorithm>

 5 #define maxn 1001

 6 using namespace std;

 7 const int inf=1<<28;

 8 

 9 int dis[maxn];

10 bool vis[maxn];

11 int n,m,x;

12 int a[maxn];

13 bool g[maxn][maxn];

14 int cnt[maxn];

15 

16 bool spfa()

17 {

18     queue<int>q;

19     memset(vis,false,sizeof(vis));

20     memset(cnt,0,sizeof(cnt));

21     for(int i=1; i<=n; i++) dis[i]=0;

22     dis[1]=100;

23     q.push(1);

24     vis[1]=true;

25     while(!q.empty())

26     {

27         int u=q.front();q.pop();

28         vis[u]=false;

29         if(u==n)

30         {

31            return true;

32         }

33         if(cnt[u]==n+1)

34         {

35             continue;

36         }

37         cnt[u]++;

38         if(cnt[u]==n+1)

39         {

40             dis[u]=inf;

41         }

42         for(int i=1; i<=n; i++)

43         {

44             if(g[u][i])

45             {

46                 if(dis[i]<dis[u]+a[i]&&(dis[u]+a[i]>0))

47                 {

48                     dis[i]=dis[u]+a[i];

49                     if(!vis[i])

50                     {

51                         vis[i]=true;

52                         q.push(i);

53                     }

54                 }

55             }

56         }

57     }

58     return false;

59 }

60 

61 int main()

62 {

63     while(scanf("%d",&n)!=EOF)

64     {

65         if(n==-1) break;

66         memset(g,false,sizeof(g));

67         for(int i=1; i<=n; i++)

68         {

69             scanf("%d",&a[i]);

70             scanf("%d",&m);

71             for(int j=0; j<m; j++)

72             {

73                 scanf("%d",&x);

74                 g[i][x]=true;

75             }

76         }

77         if(spfa())

78         {

79             printf("winnable\n");

80         }

81         else

82             printf("hopeless\n");

83     }

84     return 0;

85 }

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